const goods = [
  { sn: 1, name: 'Ipad', price: 3800 },
  { sn: 2, name: 'MacBook Air', price: 7800 },
  { sn: 3, name: 'MacBook Pro', price: 13800 },
  { sn: 4, name: 'MacBook M1', price: 15800 },
  { sn: 5, name: 'IWatch', price: 2800 },
]

let m = goods.indexOf((goods.sn = '2'))

console.table(m)
